Active louver system for controlled airflow in a multi-function automotive radiator and condenser system
A vehicle thermal management system is provided that includes two or more heat exchangers configured in a non-stacked arrangement, where separate air inlets corresponding to each of the heat exchangers allow a direct intake of ambient air. Active louver systems consisting of sets of adjustable louvers and a control actuator are used to control and regulate air flowing directly into one or more of the heat exchangers, where the adjustable louvers are either adjustable between two positions, i.e., opened and closed, or adjustable over a range of positions. Air ducts may be used to couple the output from one heat exchanger to the input of a different heat exchanger.
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This application is a continuation-in-part of U.S. patent application Ser. No. 13/150,553, filed 1 Jun. 2011, which claims benefit of the filing date of U.S. Provisional Patent Application Ser. No. 61/429,825, filed 5 Jan. 2011, the disclosures of which are incorporated herein by reference for any and all purposes.
FIELD OF THE INVENTIONThe present invention relates generally to vehicles and, more particularly, to an automotive radiator and condenser airflow system.
BACKGROUND OF THE INVENTIONVehicle cooling systems vary widely in complexity, depending primarily upon the thermal requirements of the various vehicle systems employed in the vehicle in question. In general, these cooling systems utilize heat exchangers of one form or another to transfer the heat generated by the vehicle subsystems to the surrounding ambient environment. Such heat transfer may either be performed directly, for example in the case of a simple radiator coupled to a vehicle engine, or indirectly, for example in the case of a thermal management system utilizing multiple heat transfer circuits to transfer the heat through multiple stages in order to sufficiently lower the temperature of the component in question.
In general, vehicle heat exchangers are designed to exchange heat between two different fluids, or two similar fluids that are at different temperatures, thereby helping to maintain the various vehicle systems and components within a safe and effective operating range of temperatures. One of the fluids is typically composed of a refrigerant or water, the water often mixed with ethylene glycol or propylene glycol or a similar liquid that provides anti-freeze protection at low temperatures. In many vehicle heat exchangers such as condensers and radiators, the second fluid is air which is forced to flow through the heat exchanger, either as a result of vehicle movement or through the use of a fan.
Within the automotive industry there are several types of air heat exchangers, the design of each being based on their intended application. Exemplary heat exchangers include:
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- A powertrain radiator in which a coolant-to-air heat exchanger is used to remove heat from an internal combustion engine or electric motor.
- A condenser in which a refrigerant-to-air heat exchanger is used to remove heat for cabin air conditioning systems or other systems (e.g., battery packs and power electronics) that employ refrigerant as the cooling fluid.
- A transmission oil cooler in which an oil-to-air heat exchanger is used to remove heat from the transmission via the transmission fluid.
- A steering pump oil cooler in which an oil-to-air heat exchanger is used to remove heat from the steering system via the steering fluid.
- A charge air cooler in which an air-to-air heat exchanger is used to remove heat from turbocharged (compressed) air used in the engine intake system.
For a given set of fluid temperatures, the performance of a fluid-to-fluid heat exchanger depends primarily on the surface area of the heat exchanger and the volume flow rate of the two fluids through the heat exchanger. Flow rate is commonly determined as the fluid velocity through the heat exchanger multiplied by the frontal area of the heat exchanger. Larger heat exchanger surface areas and mass flow rates result in greater heat transfer from the inner fluid to the outer fluid. An increase in these same variables, however, also results in an increase in the hydraulic losses, or pressure drop losses, which are manifested in increased aerodynamic drag (i.e., vehicle motive power), pump power, and fan power. Additionally, in a fluid-to-fluid heat exchanger, the transfer of heat between the two fluids increases as the temperature difference between the two fluids increases.
In a conventional vehicle utilizing multiple heat exchangers, regardless of whether the vehicle utilizes a combustion engine, an electric motor, or a combination of both (i.e., a hybrid), the individual heat exchangers are typically positioned one in front of the other, followed by a fan, this configuration referred to as a “stack”. In such a stacking arrangement, commonly the heat exchanger with the lowest outlet air temperature is located upstream, followed by higher temperature heat exchangers downstream. An example of such a configuration is a condenser followed directly by an engine radiator, followed by one or more fans. While this arrangement is more common with vehicles utilizing a combustion engine, hybrid vehicles may also use a stack of heat exchangers in order to provide cooling for the battery pack, power electronics and the motor. A principal drawback of the practice of stacking heat exchangers is an increase in hydraulic losses (i.e., fan power, aerodynamic drag) that result regardless of whether each heat exchanger in the stack is in active use. Additionally, since the temperature of the air entering the inner heat exchanger(s) will be the temperature of the air exiting the upstream heat exchanger which is typically higher than the ambient temperature, the efficiency and overall performance of the inner heat exchanger(s) is compromised. As a consequence, it is common practice to increase the surface area or thickness of the downstream heat exchangers to compensate for this decrease in expected performance which, in turn, adds weight and cost to the affected heat exchangers.
In an alternate arrangement, disclosed in co-pending U.S. patent application Ser. No. 13/150,553, a vehicle thermal management system is described utilizing multiple heat exchangers configured in a non-stacked arrangement. This arrangement maximizes heat transfer while minimizing the hydraulic power consumed in the process. The present invention provides an improved louver system for controlling air flow through such an arrangement of non-stacked heat exchangers.
SUMMARY OF THE INVENTIONA vehicle thermal management system is provided that is comprised of at least first and second heat exchangers configured in a non-stacked arrangement, wherein the first heat exchanger is coupled to a first vehicle cooling subsystem and the second heat exchanger is coupled to a second vehicle cooling subsystem; a first air inlet, wherein air flowing through the first air inlet flows directly into the first heat exchanger without first passing through the second heat exchanger; a second air inlet, wherein air flowing through the second air inlet flows directly into the second heat exchanger without first passing through the first heat exchanger; and an active louver system comprising a plurality of adjustable louvers that control air flowing directly through the second air inlet into the second heat exchanger, and an actuator coupled to the plurality of adjustable louvers that control the positioning of the louvers between at least a first position (e.g., fully opened) and a second position (e.g., fully closed). The actuator coupled to the adjustable louvers may be, for example, an electro-mechanical actuator or a hydraulic actuator. The actuator may control positioning of the adjustable louvers over a range of positions. The louvers may be coupled together using multiple links of a multi-link system. The louvers may be mounted within an air inlet aperture located between upper and lower bumper assemblies. Each louver may pivot about a pivot axis located along the front edge of the louver. The actuator may be coupled to a control processor, where the control processor controls louver positioning via the actuator. The system may further comprise a fan adjacent to the airflow exit surface of the second heat exchanger.
In another aspect of the invention, an air duct couples at least a portion of the airflow exit surface of the first heat exchanger to the airflow entrance surface of the second heat exchanger. A second set of adjustable louvers, located within the air duct and between the airflow exit surface of the first heat exchanger and the airflow entrance surface of the second heat exchanger, may be included to provide control of air flowing between the first and second heat exchangers within the air duct. The second set of adjustable louvers may have two positions, i.e., opened and closed, or adjustable over a range of positions between opened and closed.
In another aspect of the invention, the first heat exchanger may be centrally mounted along the vehicle centerline with the second heat exchanger mounted in a position adjacent to the first heat exchanger. The system may further include a third heat exchanger configured in a non-stacked arrangement with the first and second heat exchangers and mounted adjacent to the first heat exchanger and on an opposite side of the first heat exchanger relative to the second heat exchanger. In this configuration, a third air inlet is provided such that air flowing through the third air inlet flows directly into the third heat exchanger without first passing through the first or second heat exchangers. This configuration also includes a second plurality of adjustable louvers that control air flowing directly through the third air inlet into the third heat exchanger, and a second actuator coupled to the second plurality of adjustable louvers that control the positioning of the louvers between at least a first position (e.g., fully opened) and a second position (e.g., fully closed). Preferably the first and second actuators are independent from one another. The system may further comprise a first fan adjacent to the airflow exit surface of the second heat exchanger and a second fan adjacent to the airflow exit surface of the third heat exchanger. The system may further comprise a first air duct coupling at least a portion of the airflow exit surface of the first heat exchanger to the airflow entrance surface of the second heat exchanger and a second air duct coupling at least a second portion of the airflow exit surface of the first heat exchanger to the airflow entrance surface of the third heat exchanger. In this configuration a third set of adjustable louvers may be located within the first air duct and between the airflow exit surface of the first heat exchanger and the airflow entrance surface of the second heat exchanger, and a fourth set of adjustable louvers may be located within the second air duct and between the airflow exit surface of the first heat exchanger and the airflow entrance surface of the third heat exchanger.
A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings.
In the following text, the term “battery pack” refers to multiple individual batteries contained within a single piece or multi-piece housing, the individual batteries electrically interconnected to achieve the desired voltage and capacity for a particular application. The term “electric vehicle” as used herein may refer to an all-electric vehicle, also referred to as an EV, a plug-in hybrid vehicle, also referred to as a PHEV, or a hybrid vehicle, also referred to as a HEV, where a hybrid vehicle refers to a vehicle utilizing multiple propulsion sources one of which is an electric drive system.
Thermal management system 100, as with other illustrated embodiments described herein, includes a number of air ducts that control the flow of air through, or around, the heat exchangers. In the system illustrated in
The forward portions of the air ducting include a pair of air inlets 121 and 123, shown in phantom, which are positioned in front of heat exchangers 102 and 103, respectively. Additionally, the entrance 124 to the central heat exchanger 101 forms a third air inlet that provides a pathway for air to flow directly into heat exchanger 101. Air duct inlet 121 provides an airflow path 125 that bypasses heat exchanger 101 as shown. Similarly, air duct inlet 123 allows air to flow directly through heat exchanger 103 without passing through central heat exchanger 101, following path 127.
Thermal management system 200, shown in
While the use of multiple louvers 301-304 and 401-402 maximizes airflow control through heat exchangers 101-103, it should be understood that the invention may utilize a different number of control louvers, depending primarily upon the constraints and requirements placed on the thermal management system by the vehicle's design. For example, system 500 shown in
As previously noted, preferably the louvers are completely independent from one another. This allows fine tuning of the thermal management system depending upon the requirements of the vehicle subsystems to which the various heat exchangers are coupled. The arrangement shown in
In at least one preferred embodiment, the louvers may be positioned in a range of positions from fully open to fully closed, thus allowing fine modulation of the airflow. As a result of allowing a range of louver positions, the thermal management system may be fine-tuned to insure efficient use of the heat exchangers, i.e., achieving the airflow required for cooling while minimizing hydraulic and aerodynamic losses. This aspect of the invention is illustrated in
In an alternate embodiment, fine adjustment of the air flowing through the louvers is achieved by utilizing two or more sets of louvers for each opening where fine control is desired. Preferably each set of louvers is only capable of two positions: fully open or fully closed, thus simplifying louver operation. In an exemplary configuration shown in
In the illustrated and preferred embodiment, multiple trim pieces 1723/1724 are rigidly mounted between upper bumper assembly 1701 and lower bumper assembly 1703. Note that trim pieces 1723/1724 look like louvers as viewed from the front of the vehicle. Trim pieces 1723/1724 are primarily cosmetic in nature.
Recessed within the front vehicle assembly, and located between the upper and lower bumper assemblies, are multiple active louvers. In the preferred embodiment, the system uses three louvers 1725-1727. As shown in
At the heart of system 2000 is a thermal management control system 2001. System 2001 may be integrated within another vehicle control system or configured as a stand-alone control system. Typically control system 2001 includes a control processor as well as memory for storing a preset set of control instructions. Coupled to controller 2001 are a plurality of temperature sensors 2003 that monitor the temperature of the various vehicle components in general, and the vehicle components that are coupled to the vehicle cooling systems in particular. Exemplary components that may be monitored include the battery or batteries, motor, drive electronics, transmission, and coolant. Ambient temperature is preferably monitored as well. Depending upon the configuration of the vehicle, the charging system temperature may also be monitored. The monitored temperatures of these various components, detected at various locations throughout the vehicle, are used by control system 2001 to determine the operation of the various thermal management subsystems. In addition to preferably regulating the flow of coolant within the coolant loop(s) utilizing any of a variety of regulators 2005 (e.g., circulation pump operation or flow rate, flow valves, etc.), controller 2001 preferably controls any fans 2007 used within the system (e.g., fans 305/306, 1405/1406, 1717, etc.). Controller 2001 also controls operation of the active louvers 2009 (e.g., louvers 301-304, 401-402, 1301A-C, 1302A-C, 1303A-C, 1304A-C, 1407-1410, 1725-1727, etc.). Preferably louver control is provided by electro-mechanical actuators although other means may be used (e.g., hydraulic actuators). Preferably control system 2001 is designed to operate automatically based on programming implemented by the system's processor. Alternately, system 2000 may be manually controlled, or controlled via a combination of manual and automated control.
It should be understood that identical element symbols used on multiple figures refer to the same component, or components of equal functionality. Additionally, the accompanying figures are only meant to illustrate, not limit, the scope of the invention and should not be considered to be to scale.
Systems and methods have been described in general terms as an aid to understanding details of the invention. In some instances, well-known structures, materials, and/or operations have not been specifically shown or described in detail to avoid obscuring aspects of the invention. In other instances, specific details have been given in order to provide a thorough understanding of the invention. One skilled in the relevant art will recognize that the invention may be embodied in other specific forms, for example to adapt to a particular system or apparatus or situation or material or component, without departing from the spirit or essential characteristics thereof. Therefore the disclosures and descriptions herein are intended to be illustrative, but not limiting, of the scope of the invention which is set forth in the following claims.
Claims
1. A vehicle thermal management system, comprising:
- at least a first heat exchanger and second heat exchanger, wherein said first and second heat exchangers are configured in a non-stacked arrangement, and wherein said first heat exchanger is in thermal communication with a first vehicle cooling subsystem and said second heat exchanger is in thermal communication with a second vehicle cooling subsystem;
- a first air inlet, wherein air flowing through said first air inlet flows directly into said first heat exchanger without first passing through said second heat exchanger;
- a second air inlet, wherein air flowing through said second air inlet flows directly into said second heat exchanger without first passing through said first heat exchanger; and
- an active louver system, comprising: a plurality of adjustable louvers that control air flowing directly through said second air inlet into said second heat exchanger; and an actuator coupled to said plurality of adjustable louvers, wherein said actuator controls positioning of said plurality of adjustable louvers between at least a first position and a second position;
- wherein said plurality of adjustable louvers are mounted within an air inlet aperture located adjacent a bumper assembly, the bumper assembly having a fascia with a curvature;
- wherein at least a first adjustable louver of said plurality of adjustable louvers is configured to pivot about a pivot axis located along a front edge portion of said first adjustable louver, the pivot axis positioned adjacent the bumper assembly; and
- wherein the first adjustable louver is configured and shaped to continue the curvature of the fascia of the bumper assembly when the first adjustable louver is in an open position, such that the first adjustable louver is inclined downwards from the pivot axis so as to minimize disruption of the air flowing directly through the second air inlet.
2. The vehicle thermal management system of claim 1, wherein said actuator is an electro-mechanical actuator.
3. The vehicle thermal management system of claim 1, wherein said actuator is a hydraulic actuator.
4. The vehicle thermal management system of claim 1, wherein said first position of said plurality of adjustable louvers is fully opened and said second position of said plurality of adjustable louvers is fully closed.
5. The vehicle thermal management system of claim 1, wherein said actuator controls positioning of said plurality of adjustable louvers over a range of positions.
6. The vehicle thermal management system of claim 1, wherein said plurality of adjustable louvers are coupled together using multiple links of a multi-link system.
7. The vehicle thermal management system of claim 1, further comprising a control processor coupled to said actuator, wherein said control processor controls positioning of said plurality of adjustable louvers via said actuator.
8. The vehicle thermal management system of claim 1, further comprising a fan adjacent to an airflow exit surface of said second heat exchanger.
9. The vehicle thermal management system of claim 1, further comprising an air duct that couples an airflow exit surface of at least a portion of said first heat exchanger to an airflow entrance surface of said second heat exchanger.
10. The vehicle thermal management system of claim 9, further comprising a second plurality of adjustable louvers located within said air duct and between said airflow exit surface of said first heat exchanger and said airflow entrance surface of said second heat exchanger, wherein said second plurality of adjustable louvers control air flowing between said airflow exit surface of said first heat exchanger and said airflow entrance surface of said second heat exchanger.
11. The vehicle thermal management system of claim 10, wherein said second plurality of adjustable louvers has a first position and a second position, wherein said first position of said second plurality of adjustable louvers is opened and said second position of said second plurality of adjustable louvers is closed.
12. The vehicle thermal management system of claim 10, wherein said second plurality of adjustable louvers is adjustable over a range of positions between opened and closed.
13. The vehicle thermal management system of claim 1, wherein said first heat exchanger is centrally mounted along a vehicle centerline and said second heat exchanger is mounted in a position adjacent to said first heat exchanger.
14. The vehicle thermal management system of claim 13, further comprising:
- a third heat exchanger, wherein said third heat exchanger is configured in said non-stacked arrangement with said first and second heat exchangers, wherein said third heat exchanger is mounted in a position adjacent to said first heat exchanger and on an opposite side of said first heat exchanger relative to said second heat exchanger;
- a third air inlet, wherein air flowing through said third air inlet flows directly into said third heat exchanger without first passing through said first or second heat exchangers; and
- a second active louver system, comprising: a second plurality of adjustable louvers that control air flowing directly through said third air inlet into said third heat exchanger; and a second actuator coupled to said second plurality of adjustable louvers, wherein said second actuator controls positioning of said second plurality of adjustable louvers between at least a first position and a second position.
15. The vehicle thermal management system of claim 14, wherein operation of said first actuator is independent of operation of said second actuator.
16. The vehicle thermal management system of claim 14, further comprising a first fan adjacent to an airflow exit surface of said second heat exchanger and a second fan adjacent to an airflow exit surface of said third heat exchanger.
17. The vehicle thermal management system of claim 14, further comprising:
- a first air duct that couples a first portion of an airflow exit surface of said first heat exchanger to an airflow entrance surface of said second heat exchanger; and
- a second air duct that couples a second portion of said airflow exit surface of said first heat exchanger to an airflow entrance surface of said third heat exchanger.
18. The vehicle thermal management system of claim 17, further comprising:
- a third plurality of adjustable louvers located within said first air duct and between said airflow exit surface of said first heat exchanger and said airflow entrance surface of said second heat exchanger, wherein said third plurality of adjustable louvers control air flowing between said airflow exit surface of said first heat exchanger and said airflow entrance surface of said second heat exchanger; and
- a fourth plurality of adjustable louvers located within said second air duct and between said airflow exit surface of said first heat exchanger and said airflow entrance surface of said third heat exchanger, wherein said fourth plurality of adjustable louvers control air flowing between said airflow exit surface of said first heat exchanger and said airflow entrance surface of said third heat exchanger.
19. The vehicle thermal management system of claim 1, wherein a cross section of the curvature of the fascia comprises a step away from the air inlet aperture, the step accommodating the first adjustable louver in the open position.
20. The vehicle thermal management system of claim 1, further comprising fixed trim pieces rigidly mounted in the air inlet aperture, each of the fixed trim pieces paired with a corresponding one of the plurality of adjustable louvers, except the first adjustable louver, so that those ones of the plurality of adjustable louvers are aligned with respective ones of the fixed trim pieces when in the open position.
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Type: Grant
Filed: May 10, 2012
Date of Patent: Feb 2, 2016
Patent Publication Number: 20120222833
Assignee: Tesla Motors, Inc. (Palo Alto, CA)
Inventors: Per Thomas Vikstrom (Sunnyvale, CA), Vincent George Johnston (Half Moon Bay, CA), Franz von Holzhausen (Malibu, CA), Paul Daniel Yeomans (Oxfordshire)
Primary Examiner: Travis Ruby
Application Number: 13/468,836
International Classification: B60H 1/00 (20060101); F28D 1/04 (20060101); F28F 27/02 (20060101);